The present invention relates to an anti-fouling paint generally used for top-coat exposed to a marine environment. These anti-fouling paints prevent settlement and growth of such marine organisms as barnacles, algae and others.
Anti-fouling coating is intended to control or prevent attachment and growth of fouling organisms on surfaces immersed in sea-water. The growth of these organisms on submerged surfaces can lead to dramatic rise in fuel costs. The build-up of fouling increases the frictional resistance of the hull and drag effects, which means that a ship must use up considerably more fuel due to its increased weight and reduced speed.
One of the successful anti-fouling paints developed in recent years is the anti-fouling paint using self-polishing copolymer. U.S. Pat. No. 3,167,473 and British Patent No. 1,457,590 disclose the self-polishing copolymers formed of triorganotin salt of an olefinically unsaturated carboxylic acid and at least one olefinically unsaturated comonomer, into which other biocides/pigments are incorporated. The copolymer proves some biocidal action of the paints and hydrolyzes in sea water at a constant leaching rate.
Generally, the antifouling paint composition contains pigments and biocides such as copper, zinc, or titanium compounds to prevent attachment of marine organisms. When larger amounts of pigments and biocides are added, the erosion rate and the effectiveness of anti-fouling increase. But the anti-fouling paints pose serious environmental and health hazards by releasing tributyltin and biocides.